package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.SeckillVoucher;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.SimpleRedisLock;
import com.hmdp.utils.UserHolder;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.time.LocalDateTime;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.*;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    private ISeckillVoucherService seckillVoucherService;
    @Resource
    private RedisIdWorker redisIdWorker;
    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private RedissonClient redissonClient;

    /**
     * VoucherOrderServiceImpl类的代理对象
     * 将代理对象的作用域进行提升，方面子线程取用
     */
    private IVoucherOrderService proxy;

    //异步处理线程池
    //异步处理线程池
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    //在类初始化之后执行，因为当这个类初始化好了之后，随时都是有可能要执行的
//    @PostConstruct
//    private void init() {
//        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
//    }

    // 用于线程池处理的任务
    // 当初始化完毕后，就会去从对列中去拿信息
    //a
    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);

    //阻塞队列
 /*   private class VoucherOrderHandler implements Runnable {

        @Override
        public void run() {
            while (true) {
                try {
                    // 1.获取队列中的订单信息
                    VoucherOrder voucherOrder = orderTasks.take();
                    // 2.创建订单
                    handleVoucherOrder(voucherOrder);
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                }
            }
        }

        private void handleVoucherOrder(VoucherOrder voucherOrder) {
            //1.获取用户
            Long userId = voucherOrder.getUserId();
            // 2.创建锁对象
            RLock redisLock = redissonClient.getLock("lock:order:" + userId);
            // 3.尝试获取锁
            boolean isLock = redisLock.tryLock();
            // 4.判断是否获得锁成功
            if (!isLock) {
                // 获取锁失败，直接返回失败或者重试
                log.error("不允许重复下单！");
                return;
            }
            try {
                //注意：由于是spring的事务是放在threadLocal中，此时的是多线程，事务会失效
                 proxy.createVoucherOrder(voucherOrder);
            } finally {
                // 释放锁
                redisLock.unlock();
            }
        }
    }
*/
    //redis的stream消息队列
        public class VoucherOrderHandler implements Runnable {


        @Override
        public void run() {
            while (true) {
                try {
                    // 1.获取消息队列中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS s1 >
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create("stream.orders", ReadOffset.lastConsumed())
                    );
                    // 2.判断订单信息是否为空
                    if (list == null || list.isEmpty()) {
                        // 如果为null，说明没有消息，继续下一次循环
                        continue;
                    }
                    // 解析数据
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> value = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(value, new VoucherOrder(), true);
                    // 3.创建订单
                    createVoucherOrder(voucherOrder);
                    // 4.确认消息 XACK
                    stringRedisTemplate.opsForStream().acknowledge("s1", "g1", record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                    //处理异常消息
                    handlePendingList();
                }
            }
        }

        private void handlePendingList() {
            while (true) {
                try {
                    // 1.获取pending-list中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS s1 0
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create("stream.orders", ReadOffset.from("0"))
                    );
                    // 2.判断订单信息是否为空
                    if (list == null || list.isEmpty()) {
                        // 如果为null，说明没有异常消息，结束循环
                        break;
                    }
                    // 解析数据
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> value = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(value, new VoucherOrder(), true);
                    // 3.创建订单
                    createVoucherOrder(voucherOrder);
                    // 4.确认消息 XACK
                    stringRedisTemplate.opsForStream().acknowledge("s1", "g1", record.getId());
                } catch (Exception e) {
                    log.error("处理pendding订单异常", e);
                    try {
                        Thread.sleep(20);
                    } catch (Exception es) {
                        es.printStackTrace();
                    }
                }
            }
        }
    }

    /*
    public Result seckillVoucher(Long voucherId) {
        // 1.查询优惠券
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
        // 2.判断秒杀是否开始
        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
            // 尚未开始
            return Result.fail("秒杀尚未开始！");
        }
        // 3.判断秒杀是否已经结束
        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
            // 尚未开始
            return Result.fail("秒杀已经结束！");
        }
        // 4.判断库存是否充足
        if (voucher.getStock() < 1) {
            // 库存不足
            return Result.fail("库存不足！");
        }
        Long userId = UserHolder.getUser().getId();
//        SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
//        boolean isLock = lock.tryLock(1200);
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        boolean isLock = lock.tryLock();
        if(!isLock){
            return Result.fail("不允许重复下单");
        }
        try {
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        }finally {
            lock.unlock();
        }


    }*/
        /**
         * 加载 判断秒杀券库存是否充足 并且 判断用户是否已下单 的Lua脚本
         */
        private static final DefaultRedisScript<Long> SECKILL_SCRIPT;

        static {
            SECKILL_SCRIPT = new DefaultRedisScript<>();
            SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
            SECKILL_SCRIPT.setResultType(Long.class);
        }

        @Override
        public Result seckillVoucher(Long voucherId) {
            //获取用户
            Long userId = UserHolder.getUser().getId();
            long orderId = redisIdWorker.nextId("order");
            // 1.执行lua脚本
            Long result = stringRedisTemplate.execute(
                    SECKILL_SCRIPT,
                    Collections.emptyList(),
                    voucherId.toString(), userId.toString(), String.valueOf(orderId)
            );
            int r = result.intValue();
            // 2.判断结果是否为0
            if (r != 0) {
                // 2.1.不为0 ，代表没有购买资格
                return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
            }
            //TODO 保存阻塞队列
            // 3.返回订单id
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            this.proxy = proxy;
            return Result.ok("下单成功");


        }

//        @Transactional
//        public Result createVoucherOrder(Long voucherId) {
//            // 5.一人一单逻辑
//            // 5.1.用户id
//            Long userId = UserHolder.getUser().getId();
//            int count = query().eq("user_id", userId).eq("voucher_id", voucherId).count();
//            // 5.2.判断是否存在
//            if (count > 0) {
//                // 用户已经购买过了
//                return Result.fail("用户已经购买过一次！");
//            }
//
//            //6，扣减库存
//            boolean success = seckillVoucherService.update()
//                    .setSql("stock= stock -1")
//                    .eq("voucher_id", voucherId).gt("stock", 0)
//                    .update();
//            if (!success) {
//                //扣减库存
//                return Result.fail("库存不足！");
//            }
//            //7.创建订单
//            VoucherOrder voucherOrder = new VoucherOrder();
//            // 7.1.订单id
//            long orderId = redisIdWorker.nextId("order");
//            voucherOrder.setId(orderId);
//
//            voucherOrder.setUserId(userId);
//            // 7.3.代金券id
//            voucherOrder.setVoucherId(voucherId);
//            save(voucherOrder);
//
//            return Result.ok(orderId);
//        }
        @Transactional
        public  void createVoucherOrder(VoucherOrder voucherOrder) {
            Long userId = voucherOrder.getUserId();
            // 5.1.查询订单
            int count = query().eq("user_id", userId).eq("voucher_id", voucherOrder.getVoucherId()).count();
            // 5.2.判断是否存在
            if (count > 0) {
                // 用户已经购买过了
                log.error("用户已经购买过了");
                return ;
            }

            // 6.扣减库存
            boolean success = seckillVoucherService.update()
                    .setSql("stock = stock - 1") // set stock = stock - 1
                    .eq("voucher_id", voucherOrder.getVoucherId()).gt("stock", 0) // where id = ? and stock > 0
                    .update();
            if (!success) {
                // 扣减失败
                log.error("库存不足");
                return ;
            }
            save(voucherOrder);

        }


}
